Congenital malformations are responsible for 40 percent (%) of neonatal mortality in term infants. Congenital heart disease (CHD) affects eight out of every 1000 live-born infants and accounts for the majority of death due to congenital malformation in the first year of life. Many infants born with CHD are discharged from the hospital after birth without being diagnosed. Infants with undiagnosed CHD are at very high risk for dying at home or returning to the emergency department with cardiovascular collapse. Such delayed CHD diagnosis and treatment often results in life-threatening events and significant morbidities in these infants. Thus, early CHD diagnosis using screening techniques can be life-saving.
Clinical examination of the cardiovascular system at the time of routine newborn examination has been practiced for more than 30 years. Current guidelines recommend a routine clinical examination for all newborns at the time of discharge and again at two weeks of age in the pediatrician's office. However, research studies have shown that more than half of babies with CHD are missed by routine neonatal examination. Universal newborn screening for CHD has not been a part of routine practice because of the lack of effective screening technology.
In view of these findings, researchers have searched for techniques to aid in detection of CHD. One technique currently used to screen for CHD is pulse oximetry. Pulse oximetry is a noninvasive technique which allows a healthcare provider to monitor the percent of the patient's hemoglobin saturated with oxygen. Abnormal oxygen saturation may suggest the presence of a CHD. A second technique used may be an electrocardiogram (ECG). An ECG is a graphic or waveform produced by an electrocardiograph machine which records the changes in electrical voltage in the heart. However, each screening technique alone (pulse oximetry or ECG) has its limitations and potential for missing significant CHDs. Echocardiography has been considered for use in CHD screening, however, due to the significant costs and personel requirements associated with echocardiography, its use for universal screening is impractical.